The invention relates to wire wound screens, and particularly to such screens which are made by helically wrapping a single strand of formed wire about a plurality of widely spaced apart wire rods arranged parallel to each other in the shape of a cylinder. Typically, the wire is wedge-shaped having a rather wide, flat top portion and tapered sides which converge toward each other at a rather narrow bottom portion where the wire is welded, or otherwise attached, at each intersection it makes with a rod. In the completion of such screens, the screen cylinder is generally cut to length in a plane perpendicular to the screen axis and is then attached by welding to a sleeve type fitting. Such a perpendicular cut of the helically wrapped wire, which might typically be wound at a helix angle of about 0.5 degrees, will cause the end of the wire to be cut in a long, tapered manner, so that it terminates in a feather-like tip. This wire end, or tail, can be fragile, and is commonly peeled back from those rods to which its bottom edge is no longer attached by welding, and then broken off. It is also usually peeled away from any rod or rods which have so little left of the weld joint that the tail is not firmly retained. Once the loose tail of the screen wire has been removed, the screen is ready to be attached to end fittings which permit it to be joined to sections of pipes or other screens, for example. The least expensive and most desirable type of end fitting is a cylindrical section of tubing which can be welded to the screen. However, it will be obvious that when such a cylindrical fitting and a length of helically wrapped screen, each of which has been cut off at right angles to its axis, are placed in aligned abutting contact with each other, a gap will exist in the region where the loose tail of the wrap wire was broken off. Furthermore, the gap will have a dimension which is considerably larger than the dimension of the narrow slot formed between the adjacent wraps of wire in the wrapping operation. Since any opening larger than the screen slot width would permit particles of an undesired size to pass through the screen, it is of course necessary to seal such an opening. The customary practice has been to fill such a gap with weld filler metal, or to employ a sleeve-type fitting which has an enlarged diameter end portion which can overlie the end portion of the screen, including the gap portion. Neither practice is ordinarily desirable.
In the case where the gap is to be filled with weld metal, additional labor is necessary, and quality is dependent upon operator skill and care. Furthermore, with screens made of fine wires, it is very difficult to fill the gap without damaging the screen.
Sleeve-type fittings are only used in certain instances where the application can tolerate the increase in outside diameter of the assembly. Also, formed sleeve-type fittings are expensive compared to conventional fittings cut from tubing.